Michael J. Frank, PhD
Edgar L. Marston Professor of Cognitive & Psychological Sciences
Director, Carney Center for Computational Brain Science
Brown University
Host(s): Kaushik Lakshminarasimhan (Postdoc)
Augmenting effective working memory capacity in biological and artificial neural networks
How and why is working memory (WM) capacity limited? Traditional cognitive accounts focus either on limitations on the number or items that can be stored (slots models), or loss of precision with increasing load (resource models). I will present a neural network model of corticostriatal circuitry that can learn to reuse the same neural populations to store multiple items, leading to resource-like constraints within a slot-like system, and inducing a tradeoff between quantity and precision of information. Such “chunking” strategies are adapted as a function of reinforcement learning and WM task demands, mimicking human performance and normative models. These simulations also suggest a computational rather than anatomical limit to WM capacity. As such I will also describe a new line of work linking mechanisms of WM gating in biological networks to those that can emerge in transformer neural networks underlying language models. Despite not having memory limits, we also find that storing and accessing multiple items requires an efficient gating policy, resembling the constraints found in frontostriatal models. When learned effectively, these gating strategies support enhanced generalizationand increase the models' effective capacity to store and access multiple items in memory.
Relevant Publications:
Chunking as a Rational Strategy for Lossy Data Compression in Visual Working Memory
Venue Information:
Speaker Location: Jerome L. Greene Science Center, Kavli Auditorium, 9th Floor Lecture Hall
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Tuesdays@10 is a signature Zuckerman Institute initiative that aims to expose researchers at all levels to high-quality science and stimulate scientific discourse. The speakers featured in this series represent various fields and techniques in neuroscience, and include invited guests of the Columbia Neuroscience Seminars, the Zuckerman Institute's Local Circuits Affiliates Program, and other special seminar series through a combined, collaborative effort of one or more of the following: Columbia's Zuckerman Institute, the Center for Precision Psychiatry, the Department of Neuroscience, the Doctoral Program in Neurobiology and Behavior and the Columbia Translational Neuroscience Initiative, and with support from the Kavli Institute for Brain Science.
More information and a full schedule can be found here.